Optimization of patient protection using rare earth screen in conventional imaging procedure

The purpose of this study was to optimize patient protection using rare earth screen of speed 400 in place of conventional screen-film of speed 200. The entrance surface dose (ESD) for the two screen-film systems was determined for patients undergoing simple radiographic examinations (chest, lumbar spine and pelvis series). The determination of the ESD included backscatter factors. The ESD was the optimizing parameter and its trade off with the image quality assessment, which was surveyed based on the information obtained through standardized questionnaire. The estimated ESDs were compared with reference levels set by the Community of European Commission (CEC) for a standard adult patient. For chest PA, ESD estimates were lower than the CEC reference levels whilst that of lumbar spine AP and LAT and pelvis AP were high. Upon the adoption of rare earth screen of speed 400, a dose reduction of 33% for chest, 17% for lumbar spine and 28% for pelvis examinations was achieved. From the observations made from this study, some corrective actions such as equipment quality control of parameters that affect patient dose and image quality like kVp accuracy and consistency, mAs accuracy and consistency, optimal film processing conditions, regular film reject analysis to detect and minimize the root causes and contributory factors to poor image quality and periodic training of staff on dose reduction techniques must be undertaken. Regular assessment of patient dose and image quality, equipment quality control, adoption of faster rare earth screens and optimum radiographic technique are therefore recommended in order to achieve optimization goals. (author)